Il] THE EXISTING EQUIDAE 35 



area (especially in the white colour of their legs), is to be 

 ascribed to their being mixed with feral horses rather than 

 to any variation due to environment or any other natural cause. 



Sanson and Pietrement viewed with suspicion Prejvalsky's 

 discovery, and Pietrement placed the animal under the same sub- 

 species of Equus with Equus caballus. In this country Dr Sclater 

 took the same view as Poliakoff, whilst Sir W. Flower thought 

 that it might be an accidental hybrid between a Kiang and 

 a Mongolian or some other kind of horse. Flower's caution 

 was quite justifiable at a time when only a single skin was 

 known, although it seems not very likely that such accidental 

 unions as he postulated would occur between different species 

 of Equidae in a state of nature, in view of the well-known 

 objection of the herds of half-wild horses in the Caucasus to 

 intermix in any way. Yet, though many specimens both living 

 and dead, which have since come to hand, render it very im- 

 probable that Prejvalsky's horse is a mule, the theory has 

 retained its hold upon some naturalists down to the present 

 time, who, however, have made no attempt to test the theory 

 by experiment. 



It is to the indefatigable energy and enthusiasm of Pro- 

 fessor Cossar Ewart, who has done more than any living man 

 to advance our knowledge of the Equidae, that we owe the 

 experiments which seem likely to settle the question finally. 

 It is best to let him speak for himself 1 : " With the help of 

 Lord Arthur Cecil I succeeded early in 1902 in securing a 

 male wild Asiatic ass 2 and a couple of Mongolian pony mares 

 one a yellow dun, the other a chestnut. 'Jacob/ the wild 

 ass, was mated with the dun Mongol mare, with a brownish- 

 yellow Exmoor pony, and with a bay Shetland-Welsh pony. 

 The chestnut Mongol pony was put to a light grey Connemara 

 stallion. Of the four mares referred to three have already 

 (June) foaled, namely the Exmoor and the two Mongolian 

 ponies. The Exmoor having foaled first, her hybrid may be 

 first considered. It may be mentioned that the Exmoor pony 



1 " The Wild Horse " (Equus przewalskii Poliakoff), Proc. Royal Soc. of 

 . Edinburgh, 1903, pp. 460-8. 



- This animal, now in the Zoological Garden, Eegent's Park, is an onager 

 indicus ( = hemionus indicus, cf. p. 43). 



3 2 



